Electron beam quality masurements on the ALPHA-X Laser-plasma wakefield accelerator

Gregor H. Welsh, Maria Pia Anania, Constantin Aniculaesei, Enrico Brunetti, Ronan Timothy Liam Burgess, Silvia Cipiccia, David Clark, Bernhard Ersfeld, Mohammad Islam, Riju Issac, Grace Manahan, Thomas McCanny, Gaurav Raj, Albert Reitsma, Richard Shanks, Gregory Vieux, Mark Wiggins, Dino Jaroszynski, W. A. Gillespie, A. M. MacLeodS.B. van der Geer, M. J. de Loos

Research output: Chapter in Book/Report/Conference proceedingConference contribution book


The Advanced Laser-Plasma High-Energy Accelerators towards X-rays (ALPHA-X) programme at the University of Strathclyde is developing laser-plasma wakefield
accelerators to produce high energy, ultra-short duration electron bunches as drivers of radiation sources. Coherent emission will be produced in a free-electron laser by focussing the ultra-short electron bunches into an undulator. To achieve net gain, high peak current, low energy spread and low emittance are required. A high intensity, ultra-short pulse from a 30 TW Ti:sapphire laser
is focussed into a helium gas jet to produce femtosecond duration electron bunches in the range of 80 - 200 MeV. Beam transport is monitored using a series of Lanex screens positioned along the beam line. Measurements of the electron energy spectrum, obtained using the ALPHA-X high resolution magnetic
dipole spectrometer, are presented. The maximum central energy of the monoenergetic beam is 90 MeV and r.m.s. relative energy spreads as low as 0.8% are measured. The mean central energy is 82 r 4 MeV and mean energy
spread is 1.1 r 0.4%. We also present pepper-pot measurements of the normalised transverse emittance where mono-energetic electrons are passed through an array of 52ȝm diameter holes in tungsten. The analysis of
the pepper-pot results sets an upper limit for the normalised emittance at 5.5 ± 1ʌ mm mrad for an 82 MeV beam. With further acceleration to 1 GeV, the
relative energy spread will reduce giving beam parameters that indicate the feasibility of a compact X-ray FEL driven by a plasma-wakefield accelerator.
Original languageEnglish
Title of host publicationIPAC 2010 contributions to the proceedings
Number of pages3
Publication statusPublished - 18 Jun 2010
Event1st International Particle Accelerator Conference, IPAC’10 - Kyoto, Japan
Duration: 23 May 201028 May 2010


Conference1st International Particle Accelerator Conference, IPAC’10


  • electron beam
  • quality masurements
  • laser-plasma
  • wakefield accelerator


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